Motor vehicles having an internal combustion engines can include turbochargers to increase engine performance. However, turbochargers are not designed to operate efficiently over a wide range of engine conditions. Therefore, dual turbochargers have been developed to increase the operating range over which the turbocharger system can efficiently function. In a dual turbocharger system the turbochargers may be selectively operated via electronic actuation of turbine shut-off valves. However, turbocharger performance may be negatively impacted during transition operation in the turbochargers, such as when the one of the turbochargers is shut-off or turned on, due to delays in the wastegate actuation systems.
As such in one approach, an engine system for a motor vehicle is provided to overcome at least some of the aforementioned problems. The engine system includes a first exhaust-gas turbine in a first turbocharger driven by exhaust gas from the engine, a second exhaust-gas turbine in a second turbocharger driven by exhaust gas from the engine, a bypass coupled upstream and downstream of the first exhaust-gas turbine, and a pneumatic charge pressure control device including a bypass valve positioned in the bypass and a charge pressure control valve pneumatically coupled to the bypass valve and an intake line downstream of a first compressor included in the first turbocharger, the pneumatic charge pressure control device further including an adaptation unit pneumatically coupled to the bypass valve and an exhaust line upstream of the second exhaust-gas turbine. Using a pneumatic charge pressure control device having an adaptation unit pneumatically coupled to the exhaust line upstream of the second exhaust-gas turbine enables delays in the turbine bypass actuation to be reduced when compared to previously turbine wastegate actuation systems. As a result, turbocharger and therefore engine efficiency is increased.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. Additionally, the above issues have been recognized by the inventors herein, and are not admitted to be known.